This is a duct in a house built in 1979. The seams in the photo have been leaking for all that time.

You can see the stains where air has blown out over the years.

This is one of perhaps a few hundred places where the duct work is leaking - at seams and joints, where the ducts meet the floor registers, and inside walls.

Think of the energy loss over time! Can you say "Money, money, money," boys and girls?

More modern duct work is flexible and insulated. But even when metal duct work is used today it is sealed in two ways - with a latex "paint," which is more like peanut butter spread over seams and joints, or aluminum tape.

Either method works well to seal the duct work.

Either method will save a lot of energy and money.

Either method should be used to every extent possible with older duct work such as this.

Of course metal ducts are a favorite place for ghosts to reside. My ghost friend Mosby, who seems to follow me everywhere, can be seen waving in this thermal image.

Really.

My recommendation: with energy savings the little things can go a long way. Sealing metal duct work will save on the energy bills, of course, but also will blow more conditioned air into the house where you want it. The entire system works better and the house is more comfortable. Doing so is HIGHLY recommended. And ghost approved...

Good advice for all of us to share with our clients, Jay...I did not know there was such a thing as aluminum tape...I have seen duct tape used on the flexible areas only (unless they both look alike). Something to find at Home Depot or Lowes I assume?

Amen to that! As an EcoBroker and NAR GREEN designee, I'm a big proponent of sealing ducts. Mastic works very well, but so does Aeroseal. We end up with the latter in our homes with flat ceilings where there is no attic access to seal them manually.

My home was built in 1979 with rigid metal ducts. I aerosealed them and my bill dropped from July, 2016 $151.00 to August, 2016 $94. A HUGE drop. I must have had a big leak!

There are various ways to seal ducts, Jan. And your sealing a zillion little energy wasters added up big. These various forms of duct sealing work well, and save the green. See my post today on duct tape! You might be surprised...

Dorte - they are fine unless wrapped around a joist or rafter so tightly the slinky inside is crushed and they no longer allow air to pass. I know there are heat exchangers out there, but I have never seen one in use.

Lauren - homes are a lot of work! I have posts every spring and fall on seasonal maintenance. And if/when you own a home you should own a copy of my book on home maintenance!

Welcome aboard, Laura! My intent to to instruct. Which is why I come to AR - to be instructed! All that improves my fortes... ; >)

With energy savings the little things can go a long way. Sealing metal duct work will save on the energy bills, of course, but also will blow more conditioned air into the house where you want it. The entire system works better and the house is more comfortable. Doing so is HIGHLY recommended.

Jay does it make more sense just to replace old duct (70's ) era? I'm wondering what the cost (say an average size house of 2300 sf) would be to do so as sellers/buyers will ask about that. Or is fixing the old stuff equally as good and perhpas less expensive?

OK, you got me again. I was walking around my basement (unfinished) last night checking for leaks in my ducts with the aluminum tape. As if the honey-do list my wife gives me isn't long enough already.

Shirley - that could be due to a variety of problems! Best to call in a pro.

Thanks Richie! I love sleuthing out a problem. And sometimes I actually come up with the answer!

N&T - years ago I took an image of me from outdoors, reflected in a window while sitting on a roof. The image made me look cold. So I wrote a ghost post about it, using Virginia folklore. Tongue in cheek, of course. You can read it here.

Anna B - that sounds like a lot of cost for not so much benefit! I'd stick with trying to seal up the ducts to the best extent possible!

Stephen - I hear you can catch more vinegar with bees, or something like that, so don't worry so much about the honey when your wife gives you a list. Did I get that right? Geez, I hope so.

This is a reminder to have an HVAC tech take a look under my pier and beam house with latex paint and/or aluminum tape in hand. Both products have been used to seal ducts in my attic. Great information!